A Safety and Efficacy Study of a Range of Linaclotide Doses Administered Orally to Children Ages 6-17 Years Who Fulfill Modified Rome III Criteria for Child/Adolescent Functional Constipation (FC)

Inclusion Criteria: * Participant weighs at least 18 kg (kilograms) (39.7 lbs) * Participant meets modified Rome III criteria for child/adolescent FC: For at least 2 months before the Screening Visit, the participant has had 2 or fewer defecations (with each defecation occurring in the absence of any laxative, suppository, or enema use during the preceding 24 hours) in the toilet per week. In addition, at least once per week, patient meets 1 or more of the following: * a) History of retentive posturing or excessive volitional stool retention * b) History of painful or hard bowel movements (BMs) * c) Presence of a large faecal mass in the rectum * d) History of large diameter stools that may obstruct the toilet * e) At least one episode of fecal incontinence per week * Participant is willing to discontinue any laxatives used before the Pretreatment Visit in favor of the protocol-permitted rescue medicine * Participant has an average of fewer than 3 spontaneous BMs (SBMs) per week during the 14 days before the randomization day and up to the randomization. An SBM is defined as a BM that occurs in the absence of laxative, enema, or suppository use on the calendar day of the BM or the calendar day before the BM * Participant or participant/guardian/legally authorized representative (LAR) or caregiver is compliant with electronic diary (eDiary) by completing both the morning and evening assessments for 10 out of the 14 days immediately preceding the Randomization Visit Exclusion…